1. Technical Field
The present invention relates to voltage-controlled oscillators (VCO), and more specifically, to improvements to VCOs with respect to operating frequency ranges.
2. Related Art
In a conventional LC tank voltage-controlled oscillator (VCO) comprising an inductor and a variable capacitor, the operating frequency of the VCO depends on, among other things, the capacitance of the variable capacitor. It is desirable to increase the operating frequency range of the VCO. In one case, to increase the operating frequency range of the VCO, the operator can increase the capacitance of the variable capacitor. However, increasing the capacitance of the variable capacitor results in higher parasitic resistance in the VCO and this may cause the oscillation of the VCO to stop.
Therefore, there is a need for a VCO (and a method for operating the same) that can operate at a wider operating frequency range.